邓翠玲, 佘敦先, 张利平, 张琴, 柳鑫, 王书霞. 基于图像三维连通性识别方法的长江流域干旱事件特征[J]. 农业工程学报, 2021, 37(11): 131-139. DOI: 10.11975/j.issn.1002-6819.2021.11.015
    引用本文: 邓翠玲, 佘敦先, 张利平, 张琴, 柳鑫, 王书霞. 基于图像三维连通性识别方法的长江流域干旱事件特征[J]. 农业工程学报, 2021, 37(11): 131-139. DOI: 10.11975/j.issn.1002-6819.2021.11.015
    Deng Cuiling, She Dunxian, Zhang Liping, Zhang Qin, Liu Xin, Wang Shuxia. Characteristics of drought events using three-dimensional graph connectedness recognition method in the Yangtze River Basin, China[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(11): 131-139. DOI: 10.11975/j.issn.1002-6819.2021.11.015
    Citation: Deng Cuiling, She Dunxian, Zhang Liping, Zhang Qin, Liu Xin, Wang Shuxia. Characteristics of drought events using three-dimensional graph connectedness recognition method in the Yangtze River Basin, China[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(11): 131-139. DOI: 10.11975/j.issn.1002-6819.2021.11.015

    基于图像三维连通性识别方法的长江流域干旱事件特征

    Characteristics of drought events using three-dimensional graph connectedness recognition method in the Yangtze River Basin, China

    • 摘要: 全球变化背景下,干旱事件频发给区域水资源管理和社会经济可持续发展带来了巨大挑战,科学合理地辨识干旱发生发展过程一直是干旱研究领域的前沿与难点。该研究将图像三维连通性识别方法应用于气象干旱事件的识别和提取。在长江流域的应用表明此方法识别出的干旱事件与历史记录的吻合度较高,能有效识别气象干旱事件。基于1960—2015年标准化降水蒸散发指数(Standardized Precipitation Evapotranspiration Index, SPEI),长江流域共发生281场气象干旱事件,其中长历时干旱事件(历时大于4个月)64场。长历时干旱事件在流域中部发生次数多于东部和西部,2000年之后的发生频次、干旱面积和干旱强度大于2000年之前,单场事件发展方向以西北和东南为主。整体上,干旱事件发生频次和干旱强度在长江流域中部呈增加趋势,在流域东部和西部呈减小趋势。该研究有助于探索长江流域干旱事件发展演变规律。

       

      Abstract: Drought events occur more frequently against global warming in recent years,resulting in a great pressureto the regional water resource management, ecosystem, and sustainable socio-economic development in many regions. Identification of drought events is essential to further understand characteristics of drought onset, evolution, and recovery. In this study, taking the Yangtze River Basin (YRB) as the case study, a new recognition method was proposed to identify the regional drought events using three-dimensional graph connectednessrecognition method. This new identification was first to recognize the three-dimensional continuum with no limitation, and then to split the continuum using the threshold of occurring and overlapping areas, finally to extract the drought events with three-dimensional characteristics. The number of times to calculate the overlaid area in space was reduced significantly compared to the drought identification using clustering method, which identifies drought patches in each month using the threshold of occurring area firstly, and then merges patches in adjacent months using the threshold of overlapping area. The spatial-temporal patterns of droughts were obtained to verify the efficiency of this new method using the three-month Standardized Precipitation Evapotranspiration Index (SPEI3)in YRBfrom 1960-2015. The results showed that: 1) 1.5% of the studyarea was considered as the threshold of occurring and overlapping areas, compared with the previous official reports. The drought events identified by the new method matched very well with the historical occurred onesinthe onset, termination, and propagationin YRB. There was a significant positive correlation between the drought intensity of single drought event and the moisture deficit of surface soil in the affected region. It proved the efficiency of the new method in identifying and extracting three-dimensional drought events; 2) 281 drought events are identified in YRB from 1960-2015 and the drought duration of 64 events are larger than 4 months; 3) The duration of long duration drought events (which duration is larger than 4 months) decreased, while the drought area and drought frequency increased. Long duration droughts occurred 43 times during 1960-1999, the average drought duration and drought area were 8.1 months and 2.74×104 km2, respectively. And long duration droughts occurred 21 times during 2000-2015, the average drought duration and drought area were 7.6 months and 3.50×104 km2, respectively. The frequency of long duration drought events in the middle region of YRB is higher than that in the eastern and western regions. 4) The drought events occurred more frequently in Shaanxi, Hubei, and Sichuan provinces, while the north Yunnan and Guizhou provinces presented a relatively lower frequency. Accumulative drought intensity was large in north Guizhou, northwest and east Sichuan, and Hubeiprovinces and Chongqing City, whereas, relatively small in the north Yunnan, Jiangxi and south Jiangsu provinces. The frequency and severity of drought events presented an increasing trend in the middle region of YRB, while a decreasing trend in the western and the eastern. The center of about 50% drought events moved to the northwest, mainly due to the water vapor transference and the migration of precipitation belt. The drought events identification method proposed in this studycan effectively recognize and extract drought events withthree-dimension characteristics. The finding can provide greatly promising guidance for drought and regional water resource management.

       

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